High air flow foam bedding products

ABSTRACT

Foam bedding products including viscoelastic foam having a high airflow value that do not feel hot to the person sleeping on the products. One product is a pillow having a contoured core having sufficient firmness to provide effective support for a user and a hyper soft viscoelastic foam shell surrounding the core having sufficient firmness to maintain the appearance of a conventional pillow when supporting only a pillowcase or other bed coverings. The core may be made of higher density viscoelastic foam or of a resilient foam. Another product may be a mattress topper with or without foam cores for body support carried within slabs of high airflow viscoelastic foam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application 60/578,994, filed Jun. 12, 2004.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

FIELD OF THE INVENTION

The present invention relates to bedding products, e.g. pillows and mattress pillow tops, and more particularly to bedding products comprising viscoelastic foam that has high air flow and may be very soft and may have a support core.

BACKGROUND OF THE INVENTION

Various forms of contoured pillows have been designed to provide therapeutic support of the human body, typically the cervical spine or lumbar spine. These pillows have become quite successful. They have been designed with various inserts to allow the user to adjust the level of support. They have been made with various types of foam including resilient foam and viscoelastic foams, also known as memory foam or slow recovery foam.

However, most contoured pillows, by their very designs, do not have the appearance of a conventional pillow. They generally are made of foam, for example urethane foam, and usually have a flat bottom and squared ends with the desired contour shape on the upper surface and front and/or back edges. Even if a contoured pillow is placed in a conventional pillowcase, the unconventional shape is apparent through the pillowcase. Interior decorators find such shapes undesirable for daytime coverings for beds when they are not being used for sleeping.

While many contoured pillows are intended for use in supporting the human head and neck areas, contoured pillows are also used to support other parts of the body, for example for lumbar and knee support. The body supporting pillows are generally removed from the bed when the bed is made up, because if left in place they would appear as lumps in the bed coverings.

Many bedding products, e.g. standard pillows and mattress pillow tops or mattress toppers, are made of viscoelastic foam. The viscoelastic foam tends to take the shape of the person sleeping on the product, i.e. it contours itself to the persons head and body. This feature has made viscoelastic foam bedding products successful. While viscoelastic foam is technically an open cell type of foam, it normally has a low airflow rating. As a result of the low airflow rating, viscoelastic foam bedding products tend to feel hot to the person sleeping on the products.

SUMMARY OF THE INVENTION

Embodiments of the invention are foam bedding products including viscoelastic foam having a high air flow value. Such products provide the support advantages of viscoelastic foam, but do not feel hot to the person sleeping on the products.

An embodiment of the present invention comprises a pillow having a foam core having sufficient firmness to provide effective support for a user and a hyper soft high air flow viscoelastic foam shell surrounding the core and having sufficient firmness to maintain an outer shape of a conventional pillow when supporting only a pillowcase or other bed coverings. The core may have any desired contoured shape.

Another embodiment comprises a method for making a bedding product. Both the core and the shell may be cut from blocks of appropriate foam. The shell is cut with a desired bedding product outer shape and in some cases with a cavity in a desired contour shape. A core is cut with the same desired contour shape. The core may then be placed into the cavity in the shell.

In one embodiment, the shell is cut through from its outer surface to the cavity and may be opened to receive the core. The shell may then be permanently closed with adhesive or by sewing along the cut sides.

In one embodiment, a core may be cut from a block of foam, and positioned in a mold having a conventional pillow shape. Materials may then be reacted in the mold to produce a high air flow viscoelastic foam shell surrounding the core.

In another embodiment, the bedding product is a mattress topper comprising high air flow viscoelastic foam sized to cover a mattress top. One or more support cores may be carried in the topper. The topper may comprise two slabs of viscoelastic foam bonded together with one or more support cores positioned between the slabs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front sectional view of a simple embodiment of a pillow according to the present invention.

FIG. 2 is a top sectional view of the FIG. 1 embodiment of a pillow according to the present invention.

FIGS. 3 through 7 are side cross sectional views of various embodiments of pillows according to the present invention.

FIG. 8 is an illustration of a method of assembly of a pillow according to an embodiment of the invention.

FIG. 9 is a top sectional view of an embodiment of a pillow according to the invention.

FIG. 10 is a front view of a pillow according to an embodiment in which edges of the pillow are sewed together.

FIGS. 11 through 15 are side cross sectional views of various alternate embodiments of pillows according to the present invention.

FIG. 16 is a perspective view of a mattress topper embodiment of the invention.

FIG. 17 is a cross sectional view of the mattress topper embodiment of FIG. 16.

FIG. 18 is an illustration of a molding process for making a pillow according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In this disclosure, the term “conventional pillow shape” refers to the outer shape of a conventional pillow comprising two rectangular pieces of ticking sewed together along their edges and filled with any conventional pillow filling, e.g. down, feathers, ground foam, polyester fiber, continuous foam, etc. Reference to the top, bottom, ends or side edges, and front and back edges of a pillow are with reference to a pillow positioned on a horizontal bed surface for its normal intended use. While specific dimensions may be given for various embodiments, it is apparent that pillow sizes are somewhat standardized into sizes such as standard, queen and king, based on bed sizes. For example standard sized pillows may have a length dimension of about 22 to 24 inches, a width of from about 13 to 16 inches and a thickness of from 3.5 to 6 inches. King-sized pillows may have the same width and thickness dimensions and have a length of from about 30 to 32 inches.

In this disclosure, a “mattress topper” or “pillow top” refers to a bedding product comprising at least one layer of foam having length and width dimensions corresponding to a mattress, e.g. single size, queen size, king size, etc., that is used on top of a mattress. The foam layer is normally covered with or enclosed in a fabric layer, e.g. similar to a pillow case. The term “mattress topper” usually implies that the product is separate from a mattress, is enclosed in its own cover, and is simply positioned on top of a mattress for use. The term “pillow top” usually implies that the layer of foam is built into a mattress, i.e. is inside a fabric covering that encloses the entire mattress. The foam layer or layers and function they provide may be essentially the same in either case.

Pillows and mattress toppers are both “bedding products”. But the term “bedding products” includes any product intended to support at least part of a sleeping person. The term includes mattresses. The mattress toppers described herein may form the primary or entire supporting material in a mattress if made to a desirable mattress thickness.

Foam materials of which the embodiments of the invention are made may be specified in terms of density, e.g. pounds per cubic foot. They may also be specified in terms of load bearing capacity or firmness using measurements known as Indentation Force Deflection, IFD, or Indentation Load Deflection, ILD. The terms IFD and ILD are generally considered interchangeable. They are both a measurement of the force in pounds required to press a 50 square inch circular plate into a larger piece of foam material, e.g. a 15 inch by 15 inch square piece, about 4 to 5 inches thick. The measurement is taken for a specified percentage compression, with 25% and 65% being commonly used. The test method is set out in ASTM D3574. For example, if twenty pounds of force are required to depress the plate one inch into a four inch thick piece of foam, then the IFD of that foam is 20, or 20 pounds, at 25% deflection. The higher the IFD of a foam, the firmer the foam is.

FIGS. 1 and 2 provide cross sectional front and top views of a simple embodiment of a pillow 10 according to the invention. The pillow 10 includes a foam shell portion 12 and a core portion 14 carried within and surrounded by the shell portion 12. The shell portion 12 has a conventional pillow outer shape, i.e. generally flat upper and lower surfaces 16 and 18, which taper to an edge at ends 20 and 22 and on the front and back sides. See FIGS. 3-7 for the conventional front and back edge shape. If desired, a cloth pillowcase 24 may be provided surrounding the pillow 10. The pillowcase 24 may be made from two rectangular pieces of fabric, e.g. cotton, sewed together on three sides and may have a zipper closure or other releasable closure on a fourth side to allow the pillowcase 24 to be removed for washing.

In this embodiment, the shell 10 is preferably made of hyper soft viscoelastic urethane foam, also known as memory or slow recovery foam. It is preferred that the foam be high air flow viscoelastic foam. However, if desired, a hyper soft resilient foam may be used. For purposes of this invention, the term hyper soft means a foam having a density of from 1.5 to 5 pounds per cubic foot and preferably between about 2 and about 3 pounds per cubic foot. Hyper soft foam has an IFD value of less than six pounds at 25% deflection, preferably an IFD value between one and five pounds at 25% deflection, and more preferably an IFD value of between two and four pounds at 25% deflection. Hyper soft foam has an IFD value of less than fourteen pounds at 65% deflection, preferably an IFD value between nine and thirteen pounds at 65% deflection, and more preferably an IFD value of between ten and twelve pounds at 65% deflection. It is preferred that the shell 10 be as soft as possible, while having enough firmness to substantially retain its unloaded shape when not subjected to an external force other than the weight of a pillowcase, pillow sham, and/or other bed covering such as a comforter or bedspread.

Embodiments of the invention were assembled using shells made of a hyper soft viscoelastic foam made as follows. The formulation is described in terms of PPH, parts per hundred parts of polyol. The polyol components were 75 PPH of a viscoelastic polyol (a glycol ether polyol blend) sold under the trade name SP-170 by Peterson Chemicals, Inc. and 25 PPH of a graft or copolymer polyol sold under the trade names Voranol 3943 or HL 430 by Dow Chemical Company or sold under the trade name SP-2744 by Peterson Chemicals, Inc. A low functionality MDI, Methylene Diphenyl Diisocyanate, sold under the trade name Suprasec 7050 by Huntsman Polyurethanes, was included at 42.68 PPH. Silicone surfactant type L-618 from GE/OSi was included at 1.60 PPH. Deionized water was added at 2.60 PPH. Amine blowing catalyst sold under the trade name Niax A-133 (33% solution of Niax A-1 (70% bis (dimethylaminoethyl) ether and 30% dipropylene glycol) dissolved in dipropylene glycol), by GE/OSi was included at 0.140 PPH. Tin, i.e. stannous octoate, sold under the trade name Tcat 110 by Gulbrandsen was included at 0.22 PPH. To increase the stability of the low isocyanate index foam, a stabilizer known as GM-206 was also added at 3 PPH. Additionally, a fire retardant additive known as FireMaster 552 from Great Lakes Chemical Corp. was added at 6 pph to provide improved flammability resistance. Furthermore, an antimicrobial additive known as DM-50 from Thompson Research & Associates was added at 0.1 PPH. CS-15, an antioxidant additive from GE/Osi, was used at 1.25 PPH to reduce the potential for yellowing caused by high exotherms. These materials were mixed and formed into buns using conventional polyurethane mixing and curing equipment. While nucleating gas, e.g. nitrogen, is often used to assist in opening viscoelastic foam to improve air flow, no nucleating gas was added to achieve good air flow in making this hyper soft foam. It was found desirable to increase the mixer speed by about 60% above typical rates to achieve uniform mixing resulting in a finer cell structure and a smoother, silkier hand. In this case, the mixer was operated at 4000 rpm. The tested properties of five samples of the foam were as follows. Density ranged from 2.97 to 3.11 pounds per cubic foot. The 25% IFD ranged from 5.9 to 6.4 pounds, and the 65% IFD ranged from 13.3 to 14.4 pounds. Air flow ranged from 4 to 4.25 cubic feet per minute using the ASTM D3574 test method. While pillows with shells made with this foam provided good functional results, these IFD values and density values are considered the upper ends of the preferred ranges. Preferred specifications for this foam are: 90% compression set less than 5%; air flow at 2.5 CFM minimum; fatigue loss less than 4.0%; density: from 2.50 to 3.50 lbs/cubic foot; and, IFD(25%): from 2.0 to 4.0 lbs.

The core 14 is preferably made of urethane foam having a density of from about 2 to about 6 pounds per cubic foot, preferably from about 3 to about 5 pounds per cubic foot, and more preferably about 4 pounds per cubic foot. The core 14 preferably has an IFD value between ten and twenty pounds at 25% deflection, preferably an IFD value between about twelve and about eighteen pounds at 25% deflection, and preferably an IFD value of between about fourteen and sixteen pounds at 25% deflection. The core 14 foam is preferably a viscoelastic urethane foam. However, in alternative embodiments, resilient urethane foam may be used for the core 14, since the shell may provide a desirable level of memory foam function.

The pillow 10 of FIGS. 1 and 2 may be made in various ways. For example, the core 14 may be cut from a sheet of suitable foam which is convenient for a generally flat core 14 as shown in FIGS. 1 and 2. More complicated contoured cores may be molded into a desired shape. The shell 12 may be molded with the core 14 positioned in the mold to achieve the structure shown in FIGS. 1 and 2.

FIGS. 3 through 7 provide cross sectional end views of five other embodiments of pillows 26, 27, 28, 29 and 30 according to the present inventions. Each of the pillows 26-30 has a shell 32-36 having the same outer shape as shell 12 of FIGS. 1 and 2 which is equivalent to the shape of a conventional pillow. Each shell 32-36 is preferably made of hyper soft high air flow viscoelastic foam as described above. In these embodiments, the pillows 26-30 may have a width of about eighteen inches and a thickness of about six inches. The length of the pillows 26-30 may be from about twenty to more than thirty inches depending on whether the pillow is intended for a standard, queen or king bed as discussed above.

Each of the pillows 26-30 has a core 37-41 having some type of contoured shape and formed of a firmer foam as described above for the core 14 of FIGS. 1 and 2. Cores 37, 38, 40 and 41 each have one or more rounded lobe contour designed to provide support to the neck, i.e. the cervical spine. Core 37 has rounded lobes of different heights on front and back sides of the pillow 26, allowing the user to reverse the pillow for more or less neck support. Core 38 has a rounded lobe on only one side of the core and is flat on the other, again giving the user two different support choices. Cores 40 and 41 are each two part generally cylindrical cores for providing the same neck support regardless of which way the pillow is turned. The core 39 is a generally flat core like the core 14 of FIGS. 1 and 2. However, core 39 is positioned with one of its surfaces aligned with the vertical center of the pillow 28, that is, the core is not centered in pillow 28. Pillow 28 has different effective firmness depending on which side is placed on a bed. If the core 39 is closer to the upper side of the pillow 28, the pillow may feel firmer to the user than it may when the core 39 is closer to the lower surface of the pillow 28. Each of the pillows 26-30 may be made by molding the cores 37-40 and then molding the shells 32-36 around the cores as discussed above for pillow 10. A pillow core of the present invention may be made in any desirable shape and is not limited to those shown in FIGS. 3-7. In these embodiments, the cores are made of continuous polyurethane foam, but cores may be made of other materials. For example, the core may be an inflatable bladder and may be filled with ground foam particles so that it is self inflating and has an adjustable firmness.

An alternate method of making a pillow according to an embodiment of the present invention is described with reference to FIGS. 3, 8, 9 and 10. The foam for shell 32 and core 37 may typically be made in a large scale continuous slabstock process which produces slabstocks of foam having dimensions of two to three feet in height, four feet wide, and essentially any desired length. The slabstocks are normally cut into buns having a length of eight to ten feet, based on sizes which may be conveniently shipped and handled. In this invention, the buns are preferably cast or cut to a slab thickness corresponding to a desired pillow length, e.g. about twenty-five inches for standard bed pillows.

A shell 32 may be cut from a slab of hyper soft viscoelastic foam using a computer controlled vertical contour cutter. The cutter may be programmed with the shapes shown in FIG. 3. The cutter will cut the outer contour of the shell 32 and the contour of core 37 to form a cavity within the shell 32 which exactly matches the shape of core 37. Since this type of cutter cuts a continuous line it will also cut along the line 42 from the outer surface of shell 32 to the cavity as shown in FIGS. 3 and 8. Once these cuts have been made in a slab, the shell 32 may be opened to the form shown in FIG. 8. A waste core of hyper soft foam is produced while cutting the shell 32, and this core is removed and may be recycled. A portion of this waste hyper soft core may be incorporated into the final pillow as discussed below.

A core 37 may be cut from a slab of firmer foam using a computer controlled vertical contour cutter. The cutter may be programmed with the shape of core 37 shown in FIG. 3. Since this is the same shape used to cut a cavity in shell 32, the core 37 will fit precisely within the shell 32 as indicated in FIGS. 3 and 8. Assembly is facilitated by opening the shell 32 at the cut 42 as shown in FIG. 8, inserting the core 37 and then closing the shell 32.

In one embodiment, it is preferred that the core 37 be about six inches shorter in length than the shell 32. This can be accomplished by cutting the core 37 from a slab of foam which is six inches thinner than the slab used to cut shell 32. FIG. 9 illustrates a top cross sectional view of a pillow 26 in which the core 37 is shorter than the shell 32. If desired, short sections of hyper soft foam 44 having the same contour as the core 37 may be positioned at each end of the core 37. The sections 44 may be cut from the waste hyper soft foam core removed from the shell 32 to form a cavity, since it has the same contour shape.

With reference to FIG. 8, the process described above produces a pillow with the cross sectional shape shown in FIG. 3, including a conventional tapered pillow edge on its front and back edges. However, the ends of the pillow have a square cross section, typical of prior art contoured pillows. In one embodiment, the shell 32 may be closed along the cut 42 and the two ends by sewing with a standard bag closing machine as indicated in FIG. 10. By providing a shorter core 37, all foam at the ends of the pillow 26 is of the hyper soft density and firmness. The ends may therefore be easily compressed to form a tapered end and sewed into the tapered end shape. The use of the hyper soft core segments 44 at the ends may be preferred to avoid an irregular end seam which may occur if they are not used.

In some embodiments, the shell 32 may be bonded to itself and to the core 37 to prevent any relative movement between the core 37 and shell 32 in use. Spray-on adhesives are available for bonding urethane foam parts together. If an adhesive is used, it is preferred that the adhesive be solvent and odor free. An adhesive may be used in addition to sewing the edges as described above or in place of sewing. It has been found that using only an adhesive the side edges of the hypersoft foam may be compressed into a desirable tapered shape and held in that shape by the adhesive. Depending on the tensile strength of the shell 32, it may be desirable to use adhesive in addition to sewing to reduce the chance of tearing the foam at the stitching.

In some embodiments, it is desirable to provide a zip on cloth, e.g. cotton, pillowcase 24 as shown in FIG. 1 for each pillow made as described above with reference to FIGS. 3, 8, 9 and 10. The pillowcase 24 is preferably sized to provide a snug fit over the pillow of the present invention. The snug fit will reduce the chance of relative movement between the core 37 and the shell 32 and helps maintain a conventional outer pillow shape when the pillow is not in use.

FIGS. 11 through 15 illustrate embodiments functionally equivalent to the embodiments of FIGS. 3 through 7 respectively, but with different structures. In these embodiments, an alternative arrangement for reducing the chance of movement of the cores relative to the shells is provided. FIG. 11 illustrates a pattern for cutting a shell 46 of hyper soft foam for an embodiment like that shown in FIG. 3. In FIG. 11, the vertical cutter forms two separate cavities 48 and 50 and forms two opening cuts 52 and 54 in the front and back edges of the shell 46. The cavities 48 and 50 are separated by a narrow strip 56 of the original shell foam material. The strip 56 is continuous between the upper and lower portions of the shell 46. Two core sections of firmer foam may be cut in the shapes of the cavities 48 and 50 and inserted into the cavities 48 and 50 through the cuts 52 and 54, as illustrated in FIG. 8. Soft end portions may be placed in the cavities 48 and 50 as illustrated in FIG. 9. The cut edges 52 and 54 and the side edges may be stitched together as described with reference to FIG. 10 or bonded together with an adhesive. When this is done, the resulting pillow will have the functional characteristics of a pillow according to FIG. 3. However, the center strip 56 will more securely hold the cores in place in the shell.

FIGS. 12 and 13 illustrate pillows functionally equivalent to the pillows of FIGS. 4 and 5. However, as shown and described with reference to FIG. 11, the single piece cores of FIGS. 4 and 5 are replaced with two-piece cores. In the FIG. 12 and 13 embodiments, center connector strips 58 and 60 are provided to reduce the chance of movement of the cores.

The pillow of FIG. 14 has two cavities 62 and 64 in a shell 66, which may be identical to the cavities in shell 35 of FIG. 6. However, there is no cut through the shell 66 between the cavities 62, 64. Instead, two separate cuts 68 and 70 are provided from front and back edges of the shell 66. The shell 66 is therefore continuous from top to bottom over a majority of its surface and resists movement of cores in the cavities 62 and 64. The cut edges 66 and 70 and the side edges may be stitched together as described with reference to FIG. 10 or may be bonded together with an adhesive. When this is done, the resulting pillow will have the functional characteristics of a pillow according to FIG. 6.

The pillow of FIG. 15 has two cavities 74 in a shell 72, which may be identical to the cavities 41 in shell 36 of FIG. 7. However, there is no cut through the shell 72 between the cavities 74. Instead, two separate cuts 76 are provided from front and back edges of the shell 72. The shell 72 is therefore continuous from top to bottom over a majority of its surface and resists movement of cores in the cavities 74. The cut edges 76 and the side edges may be stitched together as described with reference to FIG. 10 or bonded together with an adhesive. When this is done, the resulting pillow will have the functional characteristics of a pillow according to FIG. 7.

As noted above, it is preferred that the shell 32 be made of hyper soft viscoelastic foam. The primary function of the foam shell is to provide a conventional pillow outer shape to the pillow when it is not being used to support a part of a user. That is, it provides a pillow according to the invention with the appearance of a conventional pillow. The shell firmness is preferably only enough to support a typical pillowcase, pillow sham, or a bed covering such as a bedspread or comforter. When a person rests his head on the pillow, the shell easily compresses to the extent that the person receives substantially all support from the contoured core. For example, at the preferred 65% IFD value of about ten to twelve pounds, the force required to compress the shell to one-third of its unloaded thickness is only about one-quarter pound per square inch. While the shell provides some support to the user, the user will easily feel and receive the benefit of the desirable contoured support.

However, another desirable function of the hyper soft shell has been discovered. The hyper soft foam is very breathable, i.e. permeable to air flow. This is in contrast to typical viscoelastic foam used in contoured pillows, which due to the required density and firmness has very low permeability and usually feels hot to the user. Prior art viscoelastic foam has a low airflow rating even though viscoelastic foam is normally classified as an open cell foam. The breathable foam shell allows air circulation between the user and the core to provide a cooler and more comfortable feel to the pillow. Air flow may be measured according to test method ASTM D3574, in which air flow in cubic feet per minute drawn through a two inch by two inch by one inch foam sample at one-half inch water column pressure differential is measured. The hyper soft foam used for the shells of the various embodiments preferably has an airflow of from two to six cubic feet per minute. Samples taken from a bun of hyper soft viscoelastic foam used in the various embodiments were tested at 4 and 4.25 cubic feet per minute.

The core firmness may be selected to provide a desired level of support for the user. Generally the firmness may be the same as prior art contoured pillows of the desired contour, e.g. one of the contours shown in FIGS. 3-7 or any other desired contour. Testing has shown that support provided by the hyper soft shell makes the core feel softer to the user than the core feels when used alone. To achieve the same feel of support, it may be desirable to increase the firmness of the core slightly as compared to similar contoured pillows used without a shell according to the invention. For the same reason, it may be desirable to use resilient foam to make the cores.

FIGS. 16 and 17 illustrate a mattress topper 80 embodiment of the present invention. This embodiment is in many ways the same as the pillow embodiments described above and is essentially a long wide thin pillow. The topper 80 may include one or more support cores 82, 83, 84 and 85, encased in a slab of high airflow viscoelastic foam 86. In one embodiment, the slab 86 comprises an upper slab 88 and a lower slab 90 having different densities and IFD values, preferably with the upper slab 88 having lower density and IFD value than the lower slab 90. The slab 86 may be made with length and width dimensions corresponding to standard mattress dimensions, e.g. seventy-five inches by fifty-four inches for a standard full size mattress.

In one embodiment, the viscoelastic foam slab 86 may be made of hyper soft viscoelastic foam as described above so that the topper 80 provides essentially the same functions as the pillow 10 of FIG. 1. That is, the topper 80 may provide a smooth bedding surface when not in use, but may provide lumbar and/or knee contoured pillow type of support when in use. The foam will also provide the high air flow advantage that makes the topper 80, and therefore the supporting mattress, feel cool to the person resting on the topper 80.

Viscoelastic foam mattresses and mattress toppers are known. The memory foam feature of viscoelastic foam is considered a desirable feature of such products by most users. The known viscoelastic foam mattresses and mattress toppers generally have higher IFD values and densities and much lower air flow ratings than the hyper soft foam described above. The formulation of the hyper soft foam described above may be adjusted to provide densities and IFD values like known viscoelastic foams while providing a high airflow value that makes the foams feel cooler when a person is resting on them. The following embodiments provide users with the support characteristics of conventional viscoelastic foam while providing much improved airflow properties.

In one embodiment, the upper slab 88 is viscoelastic foam having an IFD value of about eight and a density of about three pounds per cubic foot. In this embodiment, the slab may be a generally flat slab cut from a larger slab and may have a thickness of about one inch and length and width dimensions equal to twin, double, king, etc. mattress sizes as desired.

Foam for the upper slab 88 may be made as follows. The polyol components are 75 PPH of a viscoelastic polyol (a glycol ether polyol blend) sold under the trade name SP-170 by Peterson Chemicals, Inc. and 25 PPH of a graft or copolymer polyol such as Voranol 3943, or HL 430 by Dow, or SP-2744 by Peterson Chemicals, Inc. A low functionality MDI, Methylene Diphenyl Diisocyanate, sold under the trade name Suprasec 7050 by Huntsman Polyurethanes, is included at 50.26 PPH for an adjusted isocyanate index of 69.0. Silicone surfactant type L-618 from GE/OSi is included at 1.45 PPH. Deionized water is added at 2.90 PPH. Amine blowing catalyst sold under the trade name Niax A-133 (33% solution of Niax A-1 (70% bis (dimethylaminoethyl) ether and 30% dipropylene glycol) dissolved in dipropylene glycol), by GE/OSi is included at 0.110 PPH. Tin, i.e. stannous octoate, sold under the trade name Tcat 150 by Gulbrandsen was included at 0.63 PPH. DEOA-LF from Air Products Corporation is added at 0.50 PPH. Additionally, a fire retardant additive known as FireMaster 552 from Great Lakes Chemical Corp. is added at 6 pph to provide improved flammability resistance. Furthermore, an antimicrobial additive known as DM-50 from Thompson Research & Associates is added at 0.1 PPH. These materials are mixed and formed into buns using conventional polyurethane mixing and curing equipment. While nucleating gas, e.g. nitrogen, is often used to assist in opening viscoelastic foam to improve airflow, no nucleating gas is added to achieve good airflow in making this foam. Mixer head pressure was adjusted to 11.0 psi with a speed of 1500 RPM. Density ranged from 2.71 to 2.76 pounds per cubic foot. The 25% IFD ranged from 8.3 to 9.0 pounds. Testing of samples showed that airflow ranged from 3.0 to 4.25 cubic feet per minute using the ASTM D3574 test method. Preferred specifications for this foam are: 90% compression set less than 5%; Air Flow at 2.5 CFM minimum; Fatigue loss less than 4.0%; Density: 2.50-3.50 lbs/cubic foot; and IFD: 6.0 to 10.0 lbs.

In one embodiment, the lower slab 90 is a viscoelastic foam having an IFD value of about twelve and a density of about four pounds per cubic foot. In this embodiment, the slab may be a contoured slab cut from a larger slab and may have a thickness of about one and three quarter inch and length and width dimensions equal to twin, double, king, etc. mattress sizes as desired. The slab 90 may be cut on a computer controlled vertical contour cutter to be essentially flat on its bottom, but to have contours on the top surface matching the shapes of the support cores 82-85.

Foam for the lower slab 90 may be made as follows. The polyol components are 56 PPH of a viscoelastic polyol (a glycol ether polyol blend) sold under the trade name SP-170 by Peterson Chemicals, Inc. and 22 PPH of a graft or copolymer polyol such as Voranol 3943, or HL 430 by Dow, or SP-2744 by Peterson Chemicals, Inc. A low functionality MDI, Methylene Diphenyl Diisocyanate, sold under the trade name Suprasec 7050 by Huntsman Polyurethanes, is included at 47.73 PPH for an adjusted isocyanate index of 69.1. To increase the stability of the low isocyanate index foam, a stabilizer known as SP-370 is added at 2.0 PPH. Silicone surfactant type L-618 from GE/OSi is included at 1.00 PPH. Deionized water is added at 1.60 PPH. A gelling amine catalyst sold under the trade name Niax A-33 by GE/OSi is included at 0.300 PPH. Tin, i.e. stannous octoate, sold under the trade name Tcat 150 by Gulbrandsen is included at 0.45 PPH. Additionally, a fire retardant additive known as FireMaster 552 from Great Lakes Chemical Corp. is added at 6 pph to provide improved flammability resistance. Furthermore, an antimicrobial additive known as DM-50 from Thompson Research & Associates is added at 0.1 PPH. These materials are mixed and formed into buns using conventional polyurethane mixing and curing equipment. While nucleating gas, e.g. nitrogen, is often used to assist in opening viscoelastic foam to improve airflow, no nucleating gas was added to achieve good airflow in making this foam. Mixer head pressure was adjusted to 11.0 psi with a speed of 1500 RPM. Density of samples ranged from 3.90 to 4.10 pounds per cubic foot. The 25% IFD ranged from 9.1 to 12.5 pounds. Airflow ranged from 3.0 to 4.00 cubic feet per minute using the ASTM D3574 test method. Preferred specifications for this foam are: 90% compression set less than 5%; Air Flow at 2.5 CFM minimum; Fatigue loss less than 4.0%; Density: 3.50 to 4.50 lbs/cubic foot; and IFD: 7.0 to 13.0 lbs.

In one embodiment, the support cores 82-85 may be made of resilient urethane foam having a density of 1.8 pounds and an IFD of 27. The cores may be cut on a computer controlled vertical contour cutter to the shapes illustrated or to other desired shapes. In this embodiment, the cores 83 and 84 are positioned across the topper 80 and spaced from the centerline of the topper 80 to provide lumbar and/or knee support regardless of which way the topper 80 is placed on a mattress. In this embodiment the cores 83, 84 are each about ten inches wide and the centerline of each core 83, 84 is spaced about eleven inches from the centerline of the topper 80. If desired, only one of the cores 83 and 84 may be used to selectively provide lumbar or knee support depending on which way the topper is placed on a mattress. The cores 82 and 85 are positioned adjacent the head and foot ends of the topper 80. This positioning provides support to a pillow at the head end of a bed and may provide a more squared shaped appearance at the foot end of a bed when a bed is made up with bed coverings such as comforters, bedspreads, etc.

The foam used in the cores 82-85 may be made as follows. Based on 100 PPH of polyol, 80 PPH of Dow's Voranol 4001 HR polyol was combined with 20 PPH of Dow's Voranol 4041 HR graft polyol; 42.97 PPH of Dow's T-80 toluene diisocyanate; 2.95 PPH of added de-ionized water; 1.15 PPH of surfactant as L-2125 from GE/Osi; 0.08 PPH of A-33 gelling catalyst from GE/Osi; 0.0.08 of A-133 blowing catalyst; 2.00 PPH of DEOA-LF from Air Products Inc.; 1.25 PPH of Dow's cell-opener Voranol 4053; 0.035 PPH of Dibutytin Dilaurate as SUL-4 from GE/Osi; 5.00 PPH of CP-2 flame retardant from Gulbrandsen Chemical, and 0.056 PPH of yellow Reactint X-15 from Milliken Chemicals. Overall isocyanate index of the foam was 108.5. 3.9 liters of nitrogen gas was added to the mix head as a cell nucleator. Mixer speed was 4000 RPM with a head pressure of 12.5 psi. Typical ranges of properties for this foam are 1.75-lbs/cubic ft. to 1.85-lbs/cubic ft. with a 25% IFD of between 25 and 29 lbs. Physical test data for this foam tested an average density of 1.75-lbs/cubic ft. with an average 25% IFD of 26.2 lbs. Airflow average was tested at 4.0 CFM.

In one embodiment, the topper 80 is assembled by placing the cores 82-86 in corresponding contours or depressions on the top surface of the lower slab 90. A spray on adhesive may then be applied to the upper surface of the lower slab 90 and cores 82-86, at least around the perimeter of the lower slab 90. The upper slab 88 may then be placed on top of the lower slab 90 and cores 82-86 and bonded thereto by the adhesive. The assembled topper 80 may then be placed in an appropriately sized and shaped fabric cover like pillowcase 22 of FIG. 1 and closed with a zipper or other closure. Alternatively, the topper 80 may be positioned on top of a mattress or mattress components, e.g. springs, and covered with the same fabric cover used to cover the complete mattress.

If desired, the topper 80 may be made without any of the cores 82-85. In this case, the topper 80 provides the desirable memory foam support characteristics of known viscoelastic foams, but with substantially improved airflow. Such toppers 80 may be made from a single slab of foam or may be made from two slabs with different densities and IFD values as described above.

The above examples show that a high air flow viscoelastic foam may have an air flow value of from two to six cubic feet per minute measured according to the ASTM D3574 standard. In preferred embodiments a high air flow viscoelastic foam should have an air flow value of at least 2.5 cubic feet per minute. Foam with air flow values of at least 2.5 cubic feet per minute provide a noticeable improvement to a person resting on such foam in terms of the cooler feeling as compared to conventional viscoelastic foam. Higher values are generally preferred. As noted above, the hyper soft foam samples had measured values ranging from four to 4.25 cubic feet per minute. The more firm foam made for slab 88 had measured values from three to 4.25 cubic feet per minute. The even more firm foam made for slab 90 had measured values from three to four cubic feet per minute. All of these values are substantially greater than previously known viscoelastic foam and are considered to be high air flow viscoelastic foam.

As noted above, the embodiments of FIGS. 1-7 and 11-15 may be made by molding the shell portion 12 around a core 14. FIG. 18 illustrates a method for molding such embodiments. A two part mold 92 includes an upper mold half 94 and a lower mold half 96, meeting along a line 98. The mold 92 has a cavity 100 defining a finished pillow shape. A plurality of core supports or spikes 102 are embedded in the lower mold half 96. The supports 102 are sized and positioned so that a pillow core 104 may be pressed down onto the spikes 102 to a desired final location within a pillow. The spikes 102 restrict movement of the core 104 during molding of the shell 12. The core 104 may be any of the cores described above or have any other desired support core shape. If desired, one or more additional spikes 102 may be carried in the top mold half 94 and may be driven into the core 104 when the mold is closed to further restrict movement of the core 104 during the molding process. An appropriate quantity of an unreacted formulation of materials for making a desired urethane foam may then be mixed and placed within the cavity 100 where it may react and fill the cavity around the core 104 with the desired foam. When the foam has cured, the mold 92 may be opened and a finished pillow may be removed from the mold 92. It is desirable to apply a mold release material to the surfaces of the cavity 100 prior to each molding operation to prevent the finished pillow from sticking to the mold 92.

A formulation useful in molding a pillow as described with reference to FIG. 18 is as follows. Blended polyol (B-side component) supplied by Peterson Chemicals Inc. as MS-1 was mixed with MDI (A-side component) supplied by Huntsman Polyurethanes, Inc. as Rubinate-7304. The ratio of this mix (B/A) was 2.22 to 1. The adjusted isocyanate index was from 63.0 to 64.0. The A & B chemicals streams were held at about 70 degrees F and then combined during injection of the pillow mold. Mold temperatures were held from about 125 degrees F to about 140 degrees F. De-mold time, i.e. curing time for the formulation, was from 3.5 to 4.0 minutes. The density of the pillow mold produced was 3.10 to 3.30 lbs per cubic foot. The 25% IFD ranged from about 5 to 10 lbs. The weight of the pillow was 2.87 lbs with a size of 18″×22″, with 5″ center crown thickness.

While the present invention has been illustrated and described with reference to particular structures, materials, and methods of making, it is apparent that various substitutions of material, structural changes and method changes may be made within the scope of the present invention as defined by the appended claims. 

1. A pillow comprising: a shell portion having an outer shape of a conventional pillow and having a cavity, a core portion sized and shaped to conform to the shape of the shell cavity and carried within the shell cavity, the core portion comprising a foam material having a firmness selected to provide effective support to a user, the shell portion comprising a foam having only enough firmness to substantially maintain its outer shape when loaded with a pillowcase and/or a bed covering.
 2. A pillow according to claim 1, wherein the core has a contoured shape selected to provide support for a portion of a user.
 3. A pillow according to claim 1, wherein the shell comprises a high air flow viscoelastic foam.
 4. A pillow according to claim 1, wherein the shell comprises foam having a IFD value of less than six pounds at 25% deflection.
 5. A pillow according to claim 1, wherein the shell comprises foam having a IFD value of between one and five pounds at 25% deflection.
 6. A pillow according to claim 1, wherein the shell comprises foam having a IFD value of between two and four pounds at 25% deflection.
 7. A pillow according to claim 1, wherein the core comprises foam having a IFD value of between ten and twenty pounds at 25% deflection.
 8. A pillow according to claim 1, wherein the core comprises foam having a IFD value of between twelve and eighteen pounds at 25% deflection.
 9. A pillow according to claim 1, wherein the shell comprises foam having a density of from about two to about three pounds per cubic foot.
 10. A pillow according to claim 1, wherein the core comprises foam having a density of from about three to about five pounds per cubic foot.
 11. A method for making a pillow comprising: cutting a shell portion having an outer surface in the shape of a conventional pillow and having a cavity from a block of foam having only enough firmness to maintain the shape of the shell when the shell is loaded with a pillowcase and/or a bed covering, cutting a core portion sized and shaped to conform to the shape of the shell cavity from a block of foam material having a firmness selected so that the core provides effective support to a user, and inserting the core portion into the shell cavity.
 12. A method according to claim 11, further comprising: cutting though one side of the shell between the shell outer surface and the cavity, opening the shell before inserting the core portion into the cavity, and closing the shell after inserting the core portion into the cavity.
 13. A method according to claim 12, further comprising bonding the cut sides of the shell together and the shell to the core.
 14. A method according to claim 13, further comprising using an adhesive for bonding the cut sides of the shell together and the shell to the core.
 15. A method according to claim 12, further comprising sewing the edges of the shell portion together.
 16. A method according to claim 15, further comprising using a bag closing machine to sew the edges of the shell portion together.
 17. A method according to claim 12, further comprising placing the pillow in a cloth pillowcase sized to form a snug fit on the pillow.
 18. A method according to claim 17, wherein the pillowcase is formed of two rectangular pieces of woven fabric sewed together along three sides and closed on a fourth side by a releasable closure.
 19. A method according to claim 18, wherein the pillowcase is closed on the fourth side by a zipper.
 20. A method according to claim 11, wherein the core is cut from a block of foam which is shorter than the block of foam from which the shell is cut.
 21. A bedding product comprising viscoelastic foam having a high air flow value.
 22. A bedding product according to claim 21 wherein the foam has an air flow value of between at least two and one-half cubic feet per minute measured according to the ASTM D3574 standard.
 23. A bedding product according to claim 21 wherein the foam has an air flow value of between about two and about six cubic feet per minute measured according to the ASTM D3574 standard.
 24. A bedding product according to claim 21 wherein the foam has an air flow value of between about four and about four and one-quarter cubic feet per minute measured according to the ASTM D3574 standard.
 25. A bedding product according to claim 21, wherein the product comprises one of a pillow and a mattress topper.
 26. A bedding product according to claim 25, wherein the product comprises a shell comprising viscoelastic foam having a high air flow value and a support core carried within the shell.
 27. A method for making a pillow comprising: positioning a contoured foam core in a mold having an inner pillow shaped surface, and reacting a formulation for viscoelastic foam having a high air flow value in the mold.
 28. A method according to claim 27 further comprising: reacting a formulation for viscoelastic foam having an IFD value of less than six in the mold.
 29. A method according to claim 27 further comprising: attaching at least one spike to an inner surface of the mold, and positioning the core on the at least spike.
 30. A method according to claim 27 further comprising: coating the inner surface of the mold with mold release. 